Question

A car and a lorry are moving with same momentum. If same brake force is applied then,

• A. car comes to rest in shorter distance
• B. lorry comes to rest in shorter distance
• C. both travels the same distance before coming to rest
• D. Insufficient data

Answer 1

The correct option is B lorry comes to rest in shorter distance

$M_{car}<M_{lorry}$ & let momentum$=p$. & Force be $F$.

$\Rightarrow \left|acar\right|<\left|alorry\right|$

Now, $2as=v^2-u^2$

$\Rightarrow S_{car}=\frac{p^2}{M_{car}^2}\times \frac{M_{car}}{F}$ $=\frac{p^2}{M_{car}F}$

$\Rightarrow S_{lorry}=\frac{p^2}{M_{lorry}F}$

$\Rightarrow S_{lorry}<S_{car}$